Biological Control of Water Hyacinth Under Conditions of Maintenance Management: Can Herbicides and Insects Be Integrated?

Neochetina eichhorniae and N. bruchi. We therefore sampled water hyacinth and weevil populations at 54 sites distributed statewide. Half were under maintenance control, half were not treated with herbicides. General site conditions were assessed, demographic data were collected on weevil and plant populations, the reproductive condition of the weevils was determined, and plant nutrient and proximate composition of water hyacinth leaves were analyzed. Water hyacinth infestations under maintenance control were minimal when compared to unmanaged sites. Likewise, on a population basis, all weevil cohorts were much lower due to the paucity of plants. Plants at unmanaged sites, where weevil intensities were much higher, suffered high levels of stress and showed low growth potential. Lower percentages of the female weevils were reproductive at unmanaged sites when compared to managed sites, so densities of reproductives and immatures were similar at both site types. Reproductive status of the weevils improved with increased plant quality. Plant quality, in turn, declined as stresses arising from weevil feeding increased. Plant quality was positively correlated with plant growth potential and flower production. Thus, maintenance control improved plant nutritive quality thereby inducing reproductive vigor of the weevils, but ensuring plant regrowth and the need for future control. This suggests that biological and herbicidal controls should be integrated, using herbicides to maintain water hyacinth infestations below management thresholds but in a manner that conserves biological control agent populations. This approach would lead to improved plant nutritional quality that would, in turn, stimulate reproduction in biological control agent populations.     

Modeling the Hydrology of Climate Change in California’s Sierra Nevada for Subwatershed Scale Adaptation1

Young, Charles A., Marisa I. Escobar‐Arias, Martha Fernandes, Brian Joyce, Michael Kiparsky, Jeffrey F. Mount, Vishal K. Mehta, David Purkey, Joshua H. Viers, and David Yates, 2009. Modeling the Hydrology of Climate Change in California’s Sierra Nevada for Subwatershed Scale Adaptation. Journal of the American Water Resources Association (JAWRA) 45(6):1409‐1423. Abstract: The rainfall‐runoff model presented in this study represents the hydrology of 15 major watersheds of the Sierra Nevada in California as the backbone of a planning tool for water resources analysis including climate change studies. Our model implementation documents potential changes in hydrologic metrics such as snowpack and the initiation of snowmelt at a finer resolution than previous studies, in accordance with the needs of watershed‐level planning decisions. Calibration was performed with a sequence of steps focusing sequentially on parameters of land cover, snow accumulation and melt, and water capacity and hydraulic conductivity of soil horizons. An assessment of the calibrated streamflows using goodness of fit statistics indicate that the model robustly represents major features of weekly average flows of the historical 1980‐2001 time series. Runs of the model for climate warming scenarios with fixed increases of 2°C, 4°C, and 6°C for the spatial domain were used to analyze changes in snow accumulation and runoff timing. The results indicated a reduction in snowmelt volume that was largest in the 1,750‐2,750 m elevation range. In addition, the runoff center of mass shifted to earlier dates and this shift was non‐uniformly distributed throughout the Sierra Nevada. Because the hydrologic model presented here is nested within a water resources planning system, future research can focus on the management and adaptation of the water resources system in the context of climate change.     

Where the Waters Divide: First Nations,Tainted Water and Environmental Justice in Canada

Abstract

We have survived Canada's assault on our identity and our rights … Our survival is a testament to our determination and will to survive as a people. We are prepared to participate in Canada's future—but only on the terms that we believe to be our rightful heritage.

Wallace Labillois, Council of Elders, Kingsclear, New Brunswick

This paper argues for a strengthening of the theoretical relationship between neo-liberalism and environmental justice. Empirical research involving First Nations communities in southwestern Ontario suggests that neo-liberal reforms introduced in the mid-1990s were particularly discriminatory against Canada's indigenous peoples, serving to exacerbate historical disparities in health, environment pollution, and well-being. In particular, under neo-liberal reform in Ontario, recognition of environmental injustices has become much more difficult for First Nations communities. Furthermore, this ‘new’ form of environmental governance has broadly reduced legitimate opportunities for First Nations to participate in environmental governance that affects their health and welfare. In short, this research supports a widening of the definition of environmental justice advocated by David Schlosberg and others (Environmental Politics, 13(3) (2004), pp. 517–540; Agyeman, Bullard and Evans 2003 Agyeman, J., Bullard, R. D. and Evans, B. 2003a. “Joined-up thinking: bringing together sustainability, environmental justice and equity”. In Just Sustainabilities: Development in an Unequal World, Edited by: Agyeman, J., Bullard, R. D. and Evans, B. Cambridge, MA: MIT Press.  [Google Scholar]; Akwesasne Task Force on the Environment, Research Advisory committee 1997; Di Chiro 1998 Di Chiro, Giovanna. 1998. “Environmental Justice from the Grassroots: Reflections on History, Gender and Expertise”. In The Struggle for Ecological Democracy: Environmental Justice Movements in the United States, Edited by: Faber, D. NY: Guilford.  [Google Scholar]) if we are to understand the subtle, complex and multiple ways that this new form of environmental governance is particularly harmful to marginalized groups, such as First Nations in Canada.